/// <summary>
 /// Add a click event attribute to component to switch the actived component.
 /// </summary>
 /// <param name="builder">The builder.</param>
 /// <param name="sequence">The sequence.</param>
 protected virtual void AddClickToActiveAttribute(RenderTreeBuilder builder, int sequence)
 => builder.AddAttribute(sequence, "onclick", EventCallback.Factory.Create <MouseEventArgs>(this, e => Parent.Active(Index)));